The problem of maintaining personal security against unauthorized entry is a longstanding problem.
In instances such as hotel rooms or in the case of condominium dwellings occasions arise when the privacy and security of an occupant is compromised by the entry of a third party, using a duplicate key.
Many solutions have been advanced, or are in wide spread use, such as safety chains, in the case of hotels and apartments. These have aesthetic disadvantages, as well as requiring the user to perform a sometimes difficult operation, in applying the chain. Also, in the case of fire or other emergency, the safety chain may present a serious obsticle to the occupant in exiting the room.
Many previous efforts have been made with a view to immobilizing the lock handle, such as:
U.S. Pat. No. 1,455,627, Lawson--May 1923; PA1 U.S. Pat. No. 1,700,135, Lanes--Jan. 1929; PA1 U.S. Pat. No. 3,423,974, Bernsley--Jan. 1969; PA1 U.S. Pat. No. 3,263,462, Suroff et al.--1966; PA1 U.S. Pat. No. 3,748,882, Dusault et al.--Jul. 1973; PA1 U.S. Pat. No. 3,921,423, Hollins--Nov. 1975; PA1 U.S. Pat. No. 3,933,014, Moses--Jan. 1976; PA1 U.S. Pat. No. 4,185,483, Lupton et al.--Jan. 1980; PA1 U.S. Pat. No. 4,279,137, Cook--Jul. 1981; PA1 U.S. Pat. No. 4,673,202, Willis--Jun. 1987; PA1 U.S. Pat. No. 4,827,745, Baugh--May 1989; PA1 U.S. Pat. No. 4,869,086, Richards--Sep. 1989; PA1 U.S. Pat. No. 4,947,663, Yeager--Aug. 1990; PA1 U.S. Pat. No. 5,000,498, Upchurch--Mar. 1991; and PA1 U.S. Pat. No. 5,007,263, Taylor--Apr. 1991.
Prior arrangements are generally characterized by their complexity; their need, usually, for separate mounting and attachment; and their expense. Also, in most cases the prior arrangements depend for their successful operation upon the particular orientation of the main axis of the door lock handle, when in the locked condition, in order to ensure engagement of the locking device, to immobilize the lock handle.